Transition between a blog to e-commerce webshop, will my domain "lose" authority

[Falcopa]

Hi Seomoz'ers,

Currently I am analyzing the best possible strategy which situation is as follow:

I am having a blog with a great EMD about a specific product we are selling. The blog is currently ranking in position 1 for different keyword phrases. However I would like to make a switch from the current Wordpress blog to Magento webshop. Simply because the product should be sold through a professional webshop with many related products.

Only the homepage of mydomainname.com is optimized. I am affraid I will lose my #1 ranking when I put my webstore online on this domainname. Most likely I will lose my PA and keep my DA. Which actions should I take in order to keep the ranking in Google position 1 with the new webstore?

My best possible option I guess:

1. Replace the Wordpress blog with the Magento webstore and optimize the homepage with on-page seo of the webstore for the targeted keywords. Will this work? As the backlinks I've built are pointing all to the domainname.com (homepage).

Thanks in advance. Any more suggestions are welcome

[SparkplugDigital]

Losing rankings is a definite possibility whenever you change the code or content of your site. If you are moving to a different domain you will lose credit for the links that you've earned unless you execute a 301 redirect. If you are staying on the same domain, you want to ensure that the content remains as close to the previous version as possible including using the same URLs for your pages. You should also make sure that the internal links are carried over to the new version of the site. Any changes to your site's home page links can significantly impact how your internal pages rank (for example if you remove the homepage links to important category pages).

[Falcopa]

Thanks for your extended answer. So in fact if i have a blog online at this moment and I have optimized the homepage of the blog for a targeted keyword and have for e.g. 5 category pages with url structure domain.com/category1 and I will remain the exact url structure and content in my new magento webshop, then there will be a big chance I keep my curreny rankings, is that correct? Thanks in advance!